In this paper the quantification of quaternary mixtures of the homologous series of the alcohols methanol to n-butanol in the gaseous phase is presented. Time-resolved reflectometric interference spectroscopy (RIfS) and surface plasmon resonance spectroscopy (SPR) are used. An array consisting of two layers of a size-selective microporous polymer (Makrolon ® ) plus the polar polymer polyetherurethan (PUT) is used for RIfS measurements. The time-dependent kinetics of sorption and desorption of the analytes is evaluated by the use of neural networks. As the time-dependent sensor signals differ significantly for each analyte, quantifications with only a single microporous layer are possible. Thus, measurements using a thinner microporous layer for the SPR set-up are also performed, showing faster sorption and desorption. Therefore, measurements can be performed much faster by using the SPR set-up.It can be shown that the quantification of the quaternary mixtures can be successfully performed using a single-sensor set-up for both methods.
Spectroscopic techniques and microcalorimetry were applied to investigate a polymer-(polydimethylsiloxane; PDMS) calixarene system during interaction with propylamine and n-propanol as analyte molecules. This was done to understand the sensitivity and selectivity of this system. By these means the interesting binding site of the calixarene selector was identified and dependencies on specific properties of the polymer and the functional groups were determined. Reflectometric interference spectroscopy (RIfS) was used to characterize the kinetics whereas isothermal titration calorimetry (ITC) yielded thermodynamic data. Infrared (IR) and (1)H NMR spectroscopy allowed identification of the sensing process as an interaction between the selective group of the PDMS-calixarene system and the amino group of propylamine, and measurement of the effects on hydrogen bonds. The combination of the different spectroscopic methods and the microcalorimetric measurements broadened the understanding of this system, regarded as a model system. Thus, future tailoring of functional groups designed for improved and more selective analyte detection is possible.
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